The matter stream consisted of the stream of sub-atomic particles that resulted from the dematerialization of a transport subject. The stream was relocated from the original site of the subject, passed through the pattern buffer, transferred as an energy beam, and rematerialized into its original form again at its destination (often a transporter platform).

Although some transporter models allowed motion within the matter stream, it was advisable to remain still. Additionally, normal spatial relationships within the stream were often distorted, making objects appear differently then their actual proportions.

The matter stream was contained in the pattern buffer before rematerialization occurred. If a person was in the matter stream too long, his or her pattern would degrade to the point that rematerialization was no longer possible. Therefore, the signal resolution needed to be kept above fifty percent. (TNG: "Realm of Fear", "Encounter at Farpoint")

When the object to be transported was surrounded with victurium alloy--for example, if a person was lying under a collapsed bulkhead--resolving the matter stream was not possible and the person needed to be moved to another location or the victurium needed to be removed. (TNG: "Hero Worship")